Monday, January 28, 2008
11:00 AM
Computer Studies Bldg. Room 209
Carl Waldspurger
VMware, Inc
Overshadow: A Virtualization-Based Approach to Retrofitting Protection in Commodity Operating Systems
Commodity operating systems entrusted with securing sensitive data are remarkably large and complex, and consequently, frequently prone to compromise. To address this limitation, we introduce a virtual-machine-based system called Overshadow that protects the privacy and integrity of application data, even in the event of a total OS compromise. Overshadow presents an application with a normal view of its resources, but the OS with an encrypted view. This allows the operating system to carry out the complex task of managing an application's resources, without allowing it to read or modify them. Thus, Overshadow offers a last line of defense for application data.

Overshadow builds on multi-shadowing, a novel mechanism that presents different views of "physical" memory, depending on the context performing the access. This primitive offers an additional dimension of protection beyond the hierarchical protection domains implemented by traditional operating systems and processor architectures.

We present the design and implementation of Overshadow and show how its new protection semantics can be integrated with existing systems. Our design has been fully implemented and used to protect a wide range of unmodified legacy applications running on an unmodified Linux operating system. We evaluate the performance of our implementation, demonstrating that this approach is practical.

BIO: Carl Waldspurger is a Principal Engineer at VMware, responsible for core resource management and virtualization technologies. Prior to joining VMware, he was a researcher at the DEC/Compaq Systems Research Center. He completed his Ph.D. in computer science at MIT in 1995, receiving the ACM doctoral dissertation award. He has published numerous papers in the areas of resource management, virtualization, and operating systems, and is an inventor with more than twenty issued patents.

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